Hello,
as per the following:
Are we sure about this? I had the idea that video timing on CBM machines is completely unrelated to the jiffy clock, other than approximately.
https://en.wikipedia.org/wiki/Commodore_CBM-II

Yes, you're right, I shouldn't say "jiffy clock" :oops:

Here is what, I'm ...

Hey,
OK, so you need a 60Hz square wave generator.

You can rebuild the circuit from the original power supply, but then you are dealing with the mains - not recommended.

Using a 555 should work:

*** This is exactly what I wanted, thank you. :)
I'll build this circuit, tap into +5v lead from ...

Hello,
Is the purpose to get +5V from +12, or vice-versa, or something else? There's more to getting a well behaved switch-mode power supply (SMPS) than just doing a PWM, and it's not territory that hobbyists do well in. I might recommend going with a ready-made integrated switching regulator ...

Hey, I have somewhat, an embarrassing question. (Yeah, I’m still new to circuit design. :oops: )

What I am trying to do, is to supply a “stable” +5v 60kHz (50% duty cycle) square wave pulse signal for a replacement power supply of my CBM 710 computer. On my first attempt, on a previous replacement ...

Hey,
it appears I must be one of the luckiest guys, on the planet.

As with my original CBM 710 (B128) mother board, I just knew I toasted this thing. So, luck would have it, I just happen to come across a CBM 710 mother board, that someone was selling on eBay. Apparently, there was issue with ...

Well,
as a status update, alone way of my journey, I also got a hold of B128 – model CBM 610. This one had a with a 220-v power supply.
Being here in the US, I decided to replace the power supply on my own.

Lucky, I was able learned from others. Basically, I gutted out the original power supply ...

Hey, I like to give thanks to all who responded.

Well, like me reintroduce myself. Basically, I am career programmer for the past 29 years, primarily in Cobol and IBM mainframe assembler. So, I’m pretty much been a purely software guy, now attempting to dive into the world of digital electronics ...

It's not what you're asking for, vmarcus but I notice Jim Brain built Fake6509 which is, I gather, a workalike board to replace the 6509 - see
MOS 6509 look-alikes?
which links to the Nu6509 repo .

For backgrounders on the CBM-II line, see
https://www.floodgap.com/retrobits/ckb/secret/b128.html ...

Hey, I would like to know, has anyone ever replicated any of the old Commodore B128 computers (the ones utilizing the 6509 processors)?
Yes, I found multiple replications for the Commodore Pet.
Even here, I saw the Micro-PET (http://www.6502.org/users/andre/petindex/boards.html) :)
I suppose, I ...

Well, I’m a newbie here. Though, this is the same topic I’ve been interest in for over ago after seeing this link - https://suchprogramming.com/fpga-meets-6502/

However, as per the +5v issue, I would suggest the following: https://www.micro-nova.com/products/me2a which is an FPGA +5V tolerant I/O ...